The monitoring has been exposed by members of a blackmarket Facebook group, who complained of receiving letters out of the blue from police, warning them they were being watched.
One unidentified user received a letter from the Canterbury Organised Crime Squad, dated July 15, warned that their membership of a group suspected to be aiding illegal drug deals had been noticed.
They might wish to “review” their membership of the group, the letter suggested – and it had a card for a drug abuse helpline stapled to it.
“Police have been monitoring your Facebook profile and established that you are engaged in a Facebook group that actively sells and trades in controlled drugs,” the letter said.
“Committing offences against [drug laws] can lead to penalties, including imprisonment.”
Police confirmed on Monday that they were monitoring social media pages, and sometimes using the evidence they found to mount raids.
This is smart work by the Police. And it isn’t spying or snooping. If you’re stupid enough to join public groups devoted to criminal activity, you shouldn’t be surprised the Police take an interest.